Sizing organic fibers

ABSTRACT

Sizing of synthetic organic fibers with an aqueous mixture of a water dispersible salt of a copolymer of ethylene and one of acrylic or methacrylic acid and a hydrolyzable organo-functional silane to provide, after said fiber is dried, improved fiber abrasion resistance, lubricity, package release, gloss, and the like.

United States Patent 1191 Johnson et al. Se t. 9 1975 [54] SIZINGORGANIC FIBERS 3,249,570 5 1966 Potts et a1 260/29.6

3 19 7 1 al.. 8 [751 Inventors f Armcmk; 3,334,233 121929 393E623?Mllto" Bembe Mahopac both of 3,536,779 10/1970 Bedikian et a]. 260/8273,567,498 3 1971 Rafferty 61 al... 117/139.5 3,650,814 3 1972 Elder 117100 0 [73] Asslgnee' corpommn New 3,655,420 4/1972 Tichenor... ll7/138.8A YOrk, NY 3,661,628 5/1972 Marsden 117/126 GS 1 FiledI 22, 1973 FOREIGNPATENTS OR APPLICATIONS [21] App]. No.: 325,328 807,185 1/1959 UnitedKingdom 8/1 15.6

52 us. 01. 428/378; 427/385; 427/387; 522 j 'f f g jj fi goler 427/390;427/394; 428/391; 428/395 gen [51 Int. Cl. D06M 15/38; DO6M 15/66 [58]Field of Search.... 8/115.6;117/138.8A,138.8B, [57] ABSTRACT 1 17/138 8F, 138,8 N, 1395 A, 1395 CF, Sizing of synthetic organic fibers with anaqueous mix- 16] UZ, 161 ZA, 161 UC ture of a water dispersible salt ofa copolymer of ethylene and one of acrylic or methacrylic acid and a hy-56 References Ci d drolyzable organo-functional silane to provide, afterUNITED STATES PATENTS said fiber is dried, improved fiber abrasionresistance, 3 044 898 7/1962 Ham) 7/76 lubricity, package release,gloss, and the like.

1 3,081,193 3/1963 Stasse 117/68 13 Claims, No Drawings acid,

SIZING ORGANIC FIBERS This invention relates to the sizing of syntheticorganic fibers to enhance a variety of properties of the fibers. Moreparticularly, this invention relates to the sizing of synthetic organicfibers with an aqueous mixture of a water dispersible salt of acopolymer of ethylene and one of acrylic or methacrylic acid and ahydrolyzable organo-functional silane to provide, after said fiber isdried, improved fiber abrasion resistance, lubricity, package release,gloss, and the like.

Many organic fibers are treated with organic solvent containing sizingagents for the sole purpose of enhancing the fibers abrasion assistance.There is described herein a new sizing agent for enhancing abrasionresistance of organic fibers which is carried in water and relies uponthe hydrolysis and condensation between silicon hydrolyzable groups toimpart a variety of enhanced properties. In a particularly preferredembodiment of this invention, these sizing agents are most useful in thesizing of polyester fibers such as those based onpolyethyleneterephthalate. The sizing agent of this invention requiresless organic solvent than competitive sizing agents, yet the sizingagent of this invention wets the fiber well and can be dried quickly.Though the organo to Si ratio is below 2, preferably below about 1.5,the size of this invention provides unique lubricity, package releaseand higher level of gloss. The sizing agent of this invention provides aunique combination of properties to the fiber and possesses superiorhandling properties when used to size the fibers. The sizing agent ofthis invention is particularly desirable in sizing continuous filamentthread, particularly contin u ous filament polyester thread, or spunyarn, to be used as a stitching thread in mechanical sewing operations.

The copolymers used in making the sizes of this invention are made bythe copolymerization of ethylene and one or more of acrylic acid andmethacrylic acid. These ethylene copolymers comprise repeating ethylenemers and units of the formula where R is hydrogen or methyl. Preferably,at least 40 weight per cent of the polymer mers are ethylene and atleast about 14 weight per cent of the mers contain COOH. Mostpreferably, at least 50 weight per cent of the mers are ethylene and atleast about 16 weight per cent of the mers contain COOH.

The ethylene copolymers may also contain minor tercomponents, such asmers derived by adding to the copolymerization such monomers as maleicacid, fumaric crotonic acid, 2-heptenoic acid, 2-ethyl-2- propenoicacid, 2-butyl-2-propenoic acid, 3-phenyl-2- propenoic acid, propylene,l-butylene, Z-butylene, 1,3- butadiene, 2,5- or 2,6-norbornadiene,2-norbornene, dicyclopentadiene, vinyl'acetate (as well as vinyl alcoholderived therefrom), vinyl chloride, isoprene, 2- chloroprene, alkylacrylates r methacrylates (where the alkyl groups contain 1 to about 12carbon atoms such as methyl, 2-ethylhexyl, dodecyl, and the like),styrene, oz-methyl-styrene, betachlorostyrene, acrylamide,methacrylamide, N,N-dimethylolacrylamide, N,N-dimethylolmethacrylamide,N-vinyl-2- pyrrolidone, acrylonitrile, methacrylonitrile, alkyl vinylethers (such as alkyl of l to about 6 carbon atoms), alkyl vinyl ketones(such as alkyl of 1 to about 6 carbon atoms), and the like. However,there should be suffi- ,cient moles of ethylene and the acrylic andmethacrylic carboxylic acids available to give the desired mer contentthereof in the copolymer. 7

The ethylene copolymers typically have a molecular weight of at leastabout 6,000 and most preferably at least 12,000, to a molecular weightof up to 200,000 or more. The molecular weight should be sufficientlyhigh to provide a copolymer which is solid, such as from waxy solid totough horny resinous solid. Desirably, the copolymer has a melt indexrange below about 250 decigrams per minute at C. (ASTM D- l 23852T). Theethylene-acrylic and/or methacrylic copolymers are desirably used aswater soluble or dis persible salts when supplied to the fibers incombination with hydrolyzable organofunctional silanes.

The preferred monovalent cations forming these copolymer salts are aminogroups such as wherein each of R R and R is either hydrogen ormonovalent organic radical containing up to 10 carbon atoms. Suchorganic radicals may contain hydrophilic groups such as hydroxyl, amino,imino or cyclic ether groups wherein 2 of the organic radicals whentaken together form a heterocyclic compound.

The monovalent organic radicals can be monovalent hydrocarbon radicalssuch as alkyl, cycloalkyl, aryl, alkaryl or aralkyl. Suitable alkylradicals include methyl, ethyl and isopropyl. Representative cycloalkylradicals include cyclobutyl, cyclopentyl and cyclohexyl. Representativearyl radicals include phenyl and naphthyl. Among the alkaryl and aralkylradicals are, e.g., benzyl, cumyl, tolyl and xylyl radicals.

Representative monovalent organic radicals containing hydrophilic groupsinclude hydroxyethyl (as found in monoethanolamine, diethanolamine,triethanolamine), dimethylaminopropyl, N,N-bis( hydroxyethyl)aminoethyl, N,N-bis(2-hydroxypropyl)aminoethyl, and the cationcontaining heterocyclic radicals as found in piperazinyl, 2,5-dimethylpiperazinyl, piperidinyl, morpholinyl, and the like.

These polymer carboxyl salts can be prepared by neutralizing thestarting carboxyl containing polymer with amine bases such as trimethylammonium hydroxide, mono-methyltriethyl ammonium hydroxide,dimethyphenyl ammonium hydroxide and the like, aliphatic amines such asethanolamine, diethylamine, ethylene diamine, N-(hydroxyethyl)ethylenediamine and the like, cyclic amines such as piperazine, pyridine,poperidine, morpholine and the like. Preferred bases are alkyl ammoniumhydroxides, ammonium hydroxide, and dialkylamines.

These soluble copolymers are described in US. Pat. Nos, 3,445,362,3,264,272 and 3,321,819 and these disclosures relative to suchcopolymers are incorporated herein by reference.

The silanes provided with the copolymer characterized by the formula:

xR'siY,, V l

o. C/H\\CH,

HN, HS--, HO, and the like; provided that when X is HS-, R may contain 2carbon atoms in sequence therein separating X from Si; and Y is anyhydrolyzable 2 group such as alkoxy, aroxy, halogen, ammo, and the like.I

Specific illustrations of the aforementioned silanes are the following:

Continued The silanes containing ester groups in the organic O radicalare capable of providing hydroxyl groups by in situ hydrolysis of theester group during drying of the ethylene-acrylic'acid copolymer on thesubstrate.

The preferred silanes in the practice of this invention contain groupsin the organo moiety, preferably NH groups. These silanes in combinationwith the copolymer achieve the most desirable properties, particularlyin sizing polyester thread used in sewing applications.

The ethylene-acid copolymer salt is made into an aqueous dispersion,such as a solution or suspension, before the silane is added. The silaneis added to the dispersion alone or admixed with water. However, a watersoluble solvent which is not an active solvent for the fiber may beadded to the aqueous mixture to enhance compatibility of the copolymerand/or the silane in water and also improve the ability of the aqueouscopolymersilane dispersion to wet the fiber surface. In fact, in thepreferred practice of this invention, alcohols such as methanol, ethanoland isopropanol are addedto the dispersion for the main purpose ofenhancing wettability. Generally, one attempts to keep the amount ofalcohol, on a weight basis, at a level of no more than twice that of theamount of water em ployed.

The amount of silane employed is based on the TCOO content of thecopolymer. Generally, the moles of organo functional groups of thesilane do not exceed the moles of COO present in the copolymer, and canbe as low as about 0.05 mole of organofunctional groups (i.e., XR' informula I above) for each'mole of COO- in the copolymer thoughpreferably at least about 0.25 moles per COO group.

EXAMPLES Sample Preparation The polymer treating bath is prepared bydiluting the ethylene/acrylic acid copolymer salt dispersion withmethanol or water, and addition of the organofunctional silane. Thismixture can also be prepared as a concentrate (without alcohol or water)by addition of the silane to ethylene/acrylic acid copolymer saltdispersion. This concentrate can then be diluted to the appropriateapplication strength when needed.

Application A single continuous multifllament thread is passed throughthe treating bath containing the copolymer mixture (3-15% EAA solids).dried between 160180C. in the forced air heating chamber and allowed tocool before final winding. Thread speed was in the order of feet/min.The cured polymer loadings were in the range of 1.5 to 9% BOWF ascalculated by difference weighing. No attempt was made to hot draw(stretch) the treated thread during this operation as is common in somecommercial sizing operations. "Based on weight fiber.

Evaluation The ability of the cured polymer to adhere to the fiber( s)is evaluated objectively by repeatedly reversing the twist of thetreated thread and at the same time rapidly flexing the thread andobserving for individual filament separation and polymer flaking.Resistance to flaking was also evaluated by scraping the treated threadwith the fingernail and observing the polymer removal and flaking. I

For the purpose of rating the characteristics of th treated thread thefollowing scale was established: For Filament Separation 1. Excellentadhesion 2. Good adhesion 3. Fair adhesion 4. Poor adhesion 5. Noadhesion For resin or polymer flaking 1. No flaking 2. Slight flaking 3.Moderate flaking 4. Heavy flaking The following working examples areillustrative of this invention. All parts referred to in the Examplesare parts by weight.

EXAMPLE 1 Two hundred and twenty-one parts of ethylene/acrylic acidammonia salt dispersion (22% solids- 22 weight per cent acrylic acid) isdiluted with 279 parts methanol to which is added 8.85 parts A-l 100silane (TM of Union Carbide Corporation for (to provide moles Nl-l permole of acrylic acid). This mixture is applied, (as previouslydescribed) to 220/3 polyester sewing thread. An identical sample ofthread is treated with a similar formulation without the A-l 100. Thetreating bath polymer solids is approximately 10% by weight in allcases. Cured resin on the thread is found to be 89% BOWF. The treatedthreads are found to have the following characteristics:

Filament Separation Resin Flaking with A-l 100 2 3 without A-] 100 4-5 3EXAMPLE 2 Filament Separation Resin Flaking with A-l l 20 2-3 3 withoutA-l 120 3 The above examples serve to show the effectiveness of theamino silanes A-l and A-1 for improving the adhesion of ethylene/acrylic acid copolymers. Even at lower solids concentration as shown inExample 2 the silane still shows its effectiveness relative to thesimilar resin system, without silane, applied at a higher concentration.

EXAMPLE 3 The formulation of Example 1 is repeated but using water asthe diluent and compared with formulation of Example 1 containing A-l100 for sizing characteristics on 220/3 polyester thread. Treating bathpolymer solids are 10% and resin loadings on the treated thread areapproximately 8% in the case of the formulation of Example 1, and 10% inthe case of the formulation of this example. The treated threads arefound to have the following characteristics:

Filament Separation Rosin Flaking Example 1 2 3 Example 3 4 3-4 (using HO) This example demonstrates advantages in using methanol as the diluentfor the sizing mixture as opposed to water.

EXAMPLE 4 227.3 parts ethylene/acrylic acid ammonia salt dis persion ofExample 1 is diluted with 240.4 parts methanol. After thoroughly mixing,22.4 parts of A-l100 silane is added (0.75 moles NH per mole of acrylicacid). This mixture gelled. A second preparation is made in which thedialkylamine salt of the ethylene/acrylic acid copolymer is prepared bydiluting 227.3 parts ethylene/acrylic acid ammonia salt dispersion with240.4 parts methanol and then adding 9.9 parts diethylamine (1:1 moleratio of amine to acrylic acid). After thoroughly mixing theseingredients 22.4 parts of A-l100 silane is added (0.75 moles NH per moleof acrylic acid). This mixture is stable. This mixture is applied to220/3 polyester sewing thread as previously described. The thread sizehas a filament separation rating of l and a resin flaking rating of lThe incorporation of an amine or use of an amine salt of stronger basestrength than the A-l 100 results in a stable treating solution. Theorganic amine can be either post added to the ammonia salt dispersion orused to prepare the initial ethylene/acrylic acid salt.

EXAMPLE H 227.3 Parts ethylene/acrylic acid ammonia salt dispersion ofExample 1 is diluted with 240.4 parts methano] to which is added 9.9parts diethylamine 1: 1 mole ratio of amine to acrylic acid). Afterthoroughly mixing these ingredients 22.4 parts of A-l 100 silane isadded (0.75 moles NH per mole of acrylic acid). This mixture is thenapplied to 220/3 polyester sewing thread as previously described.Treating bath solids were approximately by weight ethylene/acrylic acidcopolymer with a resin pickup of approximately 8%. The mixtures werecompared to mixture with A-l 100 of Example 1 for sizingcharacteristics:

Moles NH Silanc/ 4 Filament Resin Mole COO- Separation Flaking Example 10.25 v 2 3 This Example 0.75 l l The use of higher ratios of aminosilaneto acrylic acid gives a more tightly crosslinked resin which is moreresistant to abrasion.

EXAMPLE 6 Thread treated with a mixture containing 0.75 moles of aminosilane per mole of acrylic acid are somewhat stiffer than is desirable.Reduction of the silane/acrylic acid ratio to 0.50 reduces thisstiffness with only a slight reduction in the abrasion resistance of thecured resin. This formulation is a preferred formulation.

The mixture with amine of Example 4 is applied to 220/3 polyesterfilament sewing thread and to 210/3 nylon filament sewing thread.Treating bath solids are approximately 10% ethylene/acrylic acid polymerwith a resin pickup of approximately 8%. Both treated samples arecompared for characteristics.

Filament Separation Abrasion (polyester) l ION What is claimed is:

l. The process which comprises treating polyester and nylon fibers withan aqueous mixture of a water dispersible salt of a copolymer ofethylene and one of acrylic or methacrylic acid which copolymer containsat least 14 weight percent, based on the weight of the copolymer, ofpolymer units therein derived from at least one of acrylic acid ormethacrylic acid, at least 40 weight percent of the polymer units areethylene, and said copolymer has a melt index below 250 decigrams perminute, and a hydrolyzable organo functional silane of the formula XRSiYwherein X contains a functional group which is condensible with acarboxylic acid, and R is a saturated hydrocarbon radical containing atleast three carbon atoms in sequence therein separating X from Si andbonded to both, provided that when X is HS-, R may contain two carbonatoms in sequence separating the HS- from Si and Y is a hydrolyzablegroup, there being at least about 0.25 mole of XR' provided by thesilane for each mole of COO.present in the copolymer; whereby to adheresaid copolymer to said fibers.

2. The process of claim 1 wherein the salt is an amine salt.

3. The process of claim 1 wherein the salt is an ammonium salt.

4. The process of claim 1 wherein the fiber isin the form of a thread.

5. The process of claim 4 wherein the thread is a sewing thread.

6. The process of claim 1 wherein the silane is an aminoorganofunctional silane.

7. The process of claim 2 wherein the fiber is a polyester fiber and thesilane is an amino organo functional silane.

8. The process of claim 7 wherein the silane is gamma-amino propyltriethoxy-silane.

9. The process of claim 7 wherein the silane is gamma-(Beta-amino-ethyl)aminopropyl triethoxy silane.

10. The product of the process of claim 1.

11. The product of the process of claim 7.

12. The product of the process of claim 8.

13. The product of the process of claim 9.

1. THE PROCESS WHICH COMPRISES TREATING POLYESTER AND NYLON FIBERS WITHAN AQUEOUS MIXTURE OF A WATER DISPERSIBLE SALT OF A COPOLYMER OFETHYLENE AND ONE OF ACRYLIC OR METHACRYLIC ACID WHICH COPOLYMER CONTAINSAT LEAST 14 WEIGHT PERCENT, BASED ON THE WEIGHT OF THE COPOLYMER, OFPOLYMER UNITS THEREIN DERIVED FROM AT LEAST ONE OF ACRYLIC ACID ORMETHACRYLIC ACID, AT LEAST 40 WEIGHT PERCENT OF THE POLYMER UNITS AREETHYLENE, AND SAID COPOLYMER HAS A MELT INDEX INDEX BELOW 250 DECIGRAMSPER MINUTE, AND HYDROLYZABLE ORGAO FUNCTIONAL SILANE OFTHE FORMULAXR1SIY3 WHEREIN X CONTAINS A FUNCTIONAL GROUP WHICH IS CONDENSIBLE WITHA CARBOXYLIC, AND R'' IS A SATURATED HYDROCARBON RADICAL CONTAINING ATLEAST THREE CARBON ATOMS IN SEQUENCE THEREIN SEPARATING X FROM SI ANDBONDED TO BOTH, PROVIDED THAT WHEN X IS HS-, R'' MAY CONTAIN TWO CARBONATOMS IN SEQUENCE SEPARATING THE HS-FROM SI AND Y IS HYDROLYZABLE GROUP,THERE BEING AT LEAST ABOUT 0.25 MOLE OF XR'' - PROVIDED BY THE SILANEFOR EACH MOLE OF COOPRESENT IN THE COPOLYMER, WHEREBY TO ADHERE SAIDCOPOLYMER TO SAID FIBERS.
 2. The process of claim 1 wherein the salt isan amine salt.
 3. The process of claim 1 wherein the salt is an ammoniumsalt.
 4. The process of claim 1 wherein the fiber is in the form of athread.
 5. The process of claim 4 wherein the thread is a sewing thread.6. The process of claim 1 wherein the silane is an aminoorganofunctional silane.
 7. The process of claim 2 wherein the fiber isa polyester fiber and the silane is an amino organo functional silane.8. The process of claim 7 wherein the silane is gamma-amino propyltriethoxy-silane.
 9. The process of claim 7 wherein the silane isgamma-(Beta-amino-ethyl) - aminopropyl triethoxy silane.
 10. The productof the process of claim
 1. 11. The product of the process of claim 7.12. The product of the process of claim
 8. 13. The product of theprocess of claim 9.